How to Polish Clear Plastics

Jul 22, 2024

How to Polish Clear Plastics

Overview

  • Types of clear plastics: Polycarbonates, Plexiglass, Lexan
  • Applications: Safety glasses, face shields, ATV/motorcycle windshields, car gauges, rearview mirrors, welder screen covers
  • Goal: Restore transparency to scratched plastic surfaces

Materials and Tools Needed

  • Buffing Wheels:
    • Various sizes depending on the tool
    • Examples: Bench grinder, variable speed polisher, hand-held drill
  • Polishing Compound:
    • Tripoli (reddish-brown color)
    • Available in various sizes (small blocks, large sticks)

Buffing Tool Setup

  • Bench Grinder/Polisher:
    • Recommended RPM: ~3,600 RPM for 6-8 inch disc
    • Larger discs cover more surface area but require careful handling
  • Variable Speed Polisher:
    • Adjustable RPM (e.g., 2,600 to 3,000 RPM)
    • Suitable for aluminum and plastics
  • Hand-Held Drill:
    • Slower RPM (~2,000 to 3,000 RPM)
    • Suitable for smaller surfaces

Polishing Process

  1. **Prepare Plastic Surface: **
    • Clean off any debris
  2. Apply Polishing Compound:
    • Light application of Tripoli
  3. Buffing Technique:
    • Keep the buffing wheel moving to avoid overheating and melting plastic
    • Use varying angles for even polishing
    • Start with more pressure (~1-2 pounds) to remove scratches, lighten up towards the end for a fine finish
  4. Finishing Touch:
    • Additional light buffing for a higher clarity finish
    • Optional: Use softer wheels or different compounds for the final polish

Examples of Polished Items

  • Safety Glasses: Quick polish, saves cost over buying new ones
  • Face Shields: Regular polishing extends life, maintains clarity
  • Mirrors: Polished side compares favorably to unpolished side, significant clarity improvement
  • Tinted Glasses: Possible, but UV coating may complicate results

Tips and Tricks

  • Avoid Overheating: Move wheel consistently, don't focus on one spot
  • Single Wheel Hack: Use a hard wheel, adjust pressure for varying results
  • Multiple Wheels: For perfection, consider investing in hard, medium, and soft wheels
  • Polishing Aluminum/Brass: Tripoli can also be used, though additional steps may be needed for 100% reflective finish

Conclusion

  • Summary: Polishing clear plastics is economical and extends the life of items
  • Extra: Demonstration of dirty vs. clean safety glasses, importance of clear vision for safety
  • Farewell: Encouragement to test and maintain equipment